For as long as drug products have been manufactured, the Biotech and Pharmaceutical industry used various methods to convey liquid products during the drug manufacturing process. In more recent years the industry's mindset has been to move away from traditional processes which relied on fixed capital intensive piping systems. Traditional systems are typically made from stainless steel or glass lined piping. Because these systems were capital intensive, drug manufacturers would go to large expense to validate cleanability and ensure no cross contamination from one batch to the next. Facility owners have had to invest in expensive large and sophisticated utility plants with chemical dosing systems and ultra-high purity steam systems necessary to sterilize the systems.
More recently manufacturing methods have trended to faster drug development and faster regulatory clearance to market. This trend is in conjunction with, and partially due to, world health authorities granting fast track approvals of vaccines and therapies to combat the new strains of mutated diseases, which we are seeing more frequently.
Today, many of the new drug manufacturing processes utilize “Single Use Systems”. These are basically pre-sterilized sub-systems manufactured from plastics. They are used once, or a limited number of times, and then discarded. For example, instead of a stainless steel vessel and piping, a typical single use system would consist of a number of plastic bag(s) connected by a series of plastic tubing sets with mechanical connection means, including tubing manifolds, between bags, tubes and other system components. Concern over the seal integrity on tubing manifolds is of paramount concern.
There are many ways a tube-to-tube connection or multi-lumen tube connection can be made. For less critical applications, methods can be as simple as a nylon cable tie or stainless crimp ring over a hose end that has a barbed fitting inserted (“tube to hose barb” connection) but for the most critical applications this type of connection may present too much risk to seal integrity. For this reason, molded, integrally molded, or overmolded, connections between tube ends are desired, and have become recognized, as a better alternative.
Here we do not mean already-molded connectors attached to tubes by mechanical means such as threading, banding, crimping, etc. Instead we refer to methods of injecting plastic around tube ends in a mold to form a molded connector that becomes attached to the tubes during the molding process. Prior art includes designs and methods to accomplish this. There are many drawbacks to the existing methods, which rely on several invasive steps in the manufacturing process, presenting high risk of potentially contaminating or damaging the interiors of the tubes. In addition, current methods are limited in the interior shape of the flow path because of the necessity of removing the temporary inserts around which the flow path is molded.
Current practice by multiple industry participants is overmolding silicone (thermoset material) around silicone tubes with temporary mold inserts. Then the silicone is cured and the inserts are removed, often by breaking them first. Multiple patents exist which describe and claim the process.